The proposed work is aimed at developing sensitive and reliable methods for early detection of cancer and monitoring the course of the disease. These objectives are based on our finding that human blood group MN precursors, T (Thomsen-Friedenreich) and Tn (precursor of T) antigens are present in reactive form on adenocarcinoma cells but not on benign and healthy cells. The T antigen present on human (breast) carcinomata elicits both humoral and cell-mediated immune (CMI) responses in patients with these lesions. Measurement of the CMI responses to T antigen will be carried out in a large number of individuals including patients with breast carcinoma, benign breast disease as well as apparently healthy people by employing leukocyte migration inhibition and leukocyte adherence inhibition assays. This approach is justified because of our promising results obtained with these assays so far. Because of our preliminary encouraging results on patients with carcinomata of other organs, we plan to extend and expand these studies to include patients with carcinoma of gastrointestinal tract and lung with appropriate controls. We plan to test the humoral immune status by measuring anti-T antibody levels in a large number of patients with carcinomata of gastrointestinal tract and lung. Follow-up studies will be performed on CMI and anti-T levels on the previously tested people to monitor the course of the disease and also to possibly evaluate the effectiveness of therapeutic measures taken. we hope to complete establishment of a method for rapid quantitation of T-Specific structures in body fluids of carcinoma patients. T- and Tn-specific structures will be isolated from human breast carcinoma cells grown in vitro and characterized.